Posted
by
timothyon Sunday June 10, 2012 @06:55PM
from the but-how-do-they-taste? dept.

A University of Colorado-Boulder team has uncovered extremophile microbes in the rocky, high-altitude Atacama desert on the Chile-Argentina border "which seem to have a different way of converting energy than their cousins elsewhere in the world." According to the researchers, "[T]hese are very different than anything else that has been cultured. Genetically, they’re at least 5 percent different than anything else in the DNA database of 2.5 million sequences." It's an exciting frontier for biologists in part because of the recurring interest in the possibility that life has existed (or does exist) on Mars; the dry, volcanic Atacama is often compared to the Martian surface.

"With their rocky terrain, thin atmosphere and high radiation, the Atacama volcanoes are some of the most similar places on Earth to the Red Planet."

“ 'If we know, on Earth, what the outer limits for life were, and they know what the paleoclimates on Mars were like, we may have a better idea of what could have lived there,' he [Steve Schmidt] said."

I may easily have missed it in the article but I saw no direct comparisons made apart from "rocky soils in the Martian-like landscape" which refers to appearance, and by my lights "most similar" does not mean "the same."

What interested me was the five percent or more difference of these various critters from current DNA database. What fascinates me is that Life has of late been found in places we'd thought it to be least likely to impossible.

I used to do extremophile research. I can chip in a little knowledge about microbial research to neutralize some of this sensationalism

Ribosomal RNA sequences are often the basis for speciation in biology. And while the human and ape species may be less than 1 percent difference, they are described to be different species. The full genomic DNA seqs may have more difference.With microbes, the rRNA threshold for a different species is 13%. There are species of E.coli that have 50% less genomic DNA (meaning beyond 50% different since they already are missing half), that are called E.coli because the rRNA is not varied enough (less than 13% different).

My point is that in the world of microbes, and furthermore extremophiles, a 5% difference is not much. That may be a sensational news point. I persnally genetically identified several organisms from the Boiling Springs Lake Microbial Observatory (65-95 deg C, pH 1.7) that were 11-12.7% different than previously described species....

The telomere issue is underway since 2 years ago. I'd love to live forever, but imagine a world where the new cannot own the world.... where the old persist and never let go of their influence. For example, today's politics largely votes the interests of 50-60 year olds. 30 years ago, the same people voted, but the politics followed their parents who were 50-60 at the time. Since people still die, I expect in 20-30 years for cannabis to

I'm glad you've found interesting work that you enjoy - that's rare enough at any time.

Yeah, the probs attendant longevity... I had the stray thought mid-Seventies that long lives or no, just given population growth, the notion of private ownership of land, for instance, would come into question. This alone, of all the possible disruptions of having a bunch of people living for, say, centuries, acts like a panic/rage button for lots of people, self included. (I've long yearned for a piece of land to build

Not to mention that they come from a life-rich planet that has given this area a multitude of different combinations to try before any became sustainable. Life on Earth can adapt to all sorts of hostile environments, but that doesn't mean that it can originate from them.

And the atmosphere has a completely different composition and density and it's much warmer and it does in fact get precipitation from time to time and large animals such as humans can survive there for extended periods. In other words, aside from practically everything important, it's a lot like Mars.

Actually, we don't KNOW that there's no life on Mars. We just don't know that there is. But we do know of no species (yet) that could survive there. If we find something that could survive there, it'll prob

For values of "survive" that does not cover metabolism or reproduction. It might be possible to bring it back to life afterwards, but it wouldn't be alive if those conditions was all it ever experienced, which is more or less the case for the martian surface.

Don't know the details of the experiment. I agree the surface of Mars is most likely sterile, but there are some strong hints that microbial life may be just below the surface. I'd also love to find out exactly what those red stains are on Europa's surface?

IIRC, there have been experiments at JPL in which bacteria were subjected to ever more Martian-like conditions, and that if the environmental change was slow enough, some bacterial successfully adapted. My brief search didn't turn up those experiments. However...

During the assembly of the Phoenix spacecraft (http://en.wikipedia.org/wiki/Phoenix_(spacecraft)) cultures taken from the clean room in which the spacecraft was assembled and tested noted a shift in the organisms cultured towards those capable of su

Given the level of interest at NASA and other space-exploration-related scientific organizations and institutes, I strongly suspect that the experiment I proposed has been done, but the report on the experiment remains unpublished -- possibly because it came up with the negative result -- no survivors. Publication bias being what it is, NASA and universities and institutes could have tons of unpublished data on this subject. The first data we're likely to hear about is when somebody DOES get a microorgani

The "arsenic based bacteria" which were supposed to revolutionize the way we viewed biology didn't even turn out to be a hoax, but bad science. Although, after RTFA, it looks as if these scientists are being a bit more cautious before making outrageous declarations.

The "arsenic based bacteria" which were supposed to revolutionize the way we viewed biology didn't even turn out to be a hoax, but bad science. Although, after RTFA, it looks as if these scientists are being a bit more cautious before making outrageous declarations.

Biologists are finding fascinating new microorganisms in harsh environments all the time - this is mostly very good science, but nothing revolutionary or remotely controversial. The microbes in TFA are interesting because there isn't an obvious energy source available (since they're non-photosynthetic). This means that they may have evolved some unique metabolic strategy. But there is no inherent reason why these microbes can't or shouldn't exist; they're just something we haven't seen before.

The arsenic bacteria article was immediately controversial because for the claims of the authors were true, it would directly conflict with some very basic chemical phenomena, and didn't make sense in light of everything else we know about cellular biochemistry. (The mere existence of microbes in such high levels of arsenic is intrinsically interesting, since they would have had to evolve tolerance for what is effectively a poison, but again hardly revolutionary.) It was doubly controversial because it didn't do a very good job experimentally supporting the primary claim, that the bacteria preferred arsenate to phosphate in nucleic acid backbones. If you're going to put forward such an extreme hypothesis, you need to really nail the evidence 100%. The hand-waving science-by-press-release was an added slap in the face. Every scientist (especially the great ones) loves a bit of PR now and again - that's why universities issue press releases like TFA - but you have to know your limits.

Wanted to add that there are bacteria (and micro-organisms, generally) found ALL THE TIME whose metabolism we don't understand: most bacteria can't be cultured in a lab because of this, and for purposes like deriving drugs produced by them (and frankly just learning about them) it's a real problem, and why species that can host DNA from other bacteria are so important (i.e. "penicillin-derived" drugs often means "penicillin were used to act upon foreign DNA and make the antibiotic of another kind of micro-o

I can't think of a single significant religion that would be adversely affected by discovery of life elsewhere in the universe; that would require some kind of direct denial of that in its canons or whatever source of authority it may happen to have. So viperidaenz--put on your non-skeptic's dunce cap!

p.s. "religious nutters" is so broad it's even worse reasoning: the Chinese 'religious' are often the kind believing in some form of pantheism where 'heaven' is believed in, an all-powerful impersonal force (o

Arguing from statistics like that is popular today and done even by some rather great minds, but it's nonetheless an abuse of statistics and numbers, and they people should know better: it just assumes and lets men become the faithful of numbers and their own assumptions, rather than real explorers and open-minded scientists.